import java.util.Arrays;

public class Test3 {
    public static void main(String[] args) {

        int[] aa = new int[]{5, 4, 3, 2, 1};
        Arrays.sort(aa);


        // 声明一个指向数组的引用(指针)
        // new是到堆中申请空间
        int[] p1 = new int[5];
        int[] p2 = new int[]{1, 2, 3, 4, 5};
        int[] p3 = {1, 2, 3, 4, 5};
        int[] p4 = new int[5];
        int[] p5;
        System.arraycopy(p2, 0, p4, 0, 2);
        p5 = p2.clone();

//        p1 = p2;

        int[][] a = new int[2][3];
        int[][] b = new int[2][];
        b[0] = new int[]{1, 2, 3};
        b[1] = new int[]{4, 5};
        b[1] = null;
        b[1] = new int[]{4, 5, 6, 7, 8, 9};
    }
}
